Prospective Polynomial Characterization of Tibial Plateau Geometry Shows No Association With Contralateral ACL Injury in Female Athletes

BACKGROUND: Anterior cruciate ligament (ACL) injuries are common in athletic people, with young female athletes at particularly high risk. After ACL injury, reconstruction, and return to sport, many sustain contralateral ACL (CACL) injuries. While tibial plateau cartilage surface geometry has been associated with first-time ACL injury risk, its role in subsequent CACL injury remains unclear. HYPOTHESIS: The normal knee of female athletes who suffered a first-time ACL injury, underwent reconstruction, returned to preinjury activities and subsequently suffered a CACL injury will have tibial plateau cartilage surface geometry that is different compared with an equivalent population who did not sustain a subsequent CACL injury. STUDY DESIGN: Prospective cohort study. LEVEL OF EVIDENCE: Level 2. METHODS: A total of 199 subjects who suffered a first-time ACL injury, had reconstruction, returned to preinjury activities and had a contralateral knee that was normal underwent bilateral magnetic resonance imaging (MRI) scan acquisitions. Tibial plateau cartilage geometry was assessed on the uninjured, normal knees using T1-weighted Fast Field Echo MRI. Parasagittal slices at maximum cartilage concavity in medial and lateral compartments of the tibia were characterized by fitting fifth-order polynomials. Female athletes who sustained a CACL injury within 4 years of reconstruction and return to sport (n = 12) were matched and compared with a group of female athletes who did not sustain CACL injury (n = 24). Random coefficient mixed-effects regression was used to assess group differences in polynomial functions. RESULTS: = 0.18) compartments. CONCLUSION: These findings suggest that characterization of tibial plateau cartilage geometry in the normal knee of subjects who underwent reconstruction after a first-time ACL injury is insufficient to predict who will on go on to suffer a subsequent CACL injury. CLINICAL RELEVANCE: More comprehensive predictive models incorporating anatomic, biomechanical, and psychological factors are likely needed to identify those at increased risk for CACL injury after a first-time ACL injury and reconstruction.